Soft robots, known for their flexible and gentle movements, have gained prominence in precision tasks and handling delicate objects. Most soft grippers developed thus far have relied on molding processes using high-elasticity rubber, which requires additional molds to produce new shapes, limiting design flexibility. To address this constraint, we present a novel approach of fabricating pneumatic soft grippers using thermoplastic polyurethanes (TPU) through the Fused Filament Fabrication (FFF) technique. The FFF technique enables the creation of various gripper shapes without the need for additional molds, allowing for enhanced design freedom. The soft grippers were designed to respond to applied air pressure, enabling controlled bending actions. To evaluate their performance, we conducted quantitative measurements of the gripper’s shape deformation under different air pressure conditions. Moreover, force measurements were performed during gripper operation by varying the applied air pressure and adjusting the mounting angle. The results of this study provide valuable insights into the design and control of soft grippers fabricated using TPU and the FFF process. This approach offers promising opportunities for employing soft robots in various fields and paves the way for further advancements in robotics technology.
Citations
Citations to this article as recorded by
Heated Syringe Extrusion for Soft Gripper Fabrication in Additive Manufacturing Kwang Yeol Yu, Woo Jin Jeong, In Hwan Lee International Journal of Precision Engineering and Manufacturing-Smart Technology.2025; 3(1): 59. CrossRef
Multi-material additive manufacturing process design of sensor embedded soft gripper Kwang Yeol Yu, Hochan Kim, In Hwan Lee Sensors and Actuators A: Physical.2025; 386: 116322. CrossRef
Application of Image Recognition Technology in Nozzle Cleaning for Material Extrusion Additive Manufacturing Processes Ho-Chan Kim, Yong-Hwan Bae, Hae-Yong Yun, In-Hwan Lee Journal of the Korean Society of Manufacturing Process Engineers.2024; 23(11): 20. CrossRef
Construction of a Pneumatic Control System for Soft Gripper Seongyeon Kim, Kiseong Kim, Jongho Shin, Jungho Cho Journal of the Korean Society of Manufacturing Process Engineers.2024; 23(6): 30. CrossRef
The gear overlap ratio shows the characteristics of the spur gear and the helical gear and varies according to the torsional angle. The gear ratio, tooth width, and center distance, which are restricted in a space of performance and manufacturing and design in the gearbox, are fixed. A parametric study on modules, the number of teeth, and torsion angles was conducted to analyze the relationship between the overlap ratio and PPTE. Then, contact analysis was performed by correcting the tooth profile to improve the transmission error. Contact analysis was performed through correction of the tooth modification to improve transmission error, and the noise was analyzed according to the overlap ratio by applying a noise prediction equation.
Citations
Citations to this article as recorded by
Study on the Modification of the Contact Pattern and Teeth Shape of Tapping Device Drive Gears Sung-Min Moon, Yong-Woo Park, Do-Young Lee, Sung-Ki Lyu Journal of the Korean Society of Manufacturing Process Engineers.2025; 24(9): 76. CrossRef
A Study on the High Efficiency and Low Noise Design of Electric Industrial Gearboxes Nam Yong Kim, Jin-Uk Baek, Sung Ki Lyu Journal of the Korean Society for Precision Engineering.2024; 41(4): 243. CrossRef
Optimal Design of Surface Pressure Strength to Prevent Gear System Pitting Phenomenon Gi-Myung Gwak, Jin-Uk Baek, Nam-Yong Kim, Sung-Ki Lyu Journal of the Korean Society of Manufacturing Process Engineers.2024; 23(1): 76. CrossRef
Development of a Prediction Model for the Gear Whine Noise of Transmission Using Machine Learning Sun-Hyoung Lee, Kwang-Phil Park International Journal of Precision Engineering and Manufacturing.2023; 24(10): 1793. CrossRef
In this work, precise gas pressure control based on a closed pneumatic circuit was achieved with a mechanically driven gas pressure controller (MDGPC), consisting of a variable-volume bellows chamber and linear actuator. The linear actuator was employed to change an axial dimension of the bellows chamber with the proportional (P) and proportional-integral (PI) controls for fast, stable, and precise pressure control of the gas inside the bellows chamber. The pressure control stability and resolution of the MDGPC were approximately 1.5 Pa and 10 Pa for the P control and 1 Pa and 5 Pa for the PI control, respectively. Despite the more stable and precise control characteristics of the PI control method, overshoots and undershoots observed during the set-point pressure changes and recoveries from pressure disturbances rendered it unsuitable for the MDGPC control method. In contrast, the MDGPC operated under the P control did not show any significant overshoots or undershoots when the set-point pressure abruptly changed or when the MDGPC was exposed to pressure disturbances. Therefore, it was concluded that a fast, precise, and stable gas pressure control in a closed manner was attainable with the MDGPC under the P control.
Citations
Citations to this article as recorded by
Pneumatic temperature control characteristics of a variable-load heat source with a pressure-controlled loop heat pipe Bomi Nam, Wukchul Joung International Communications in Heat and Mass Transfer.2025; 166: 109219. CrossRef
Temperature uniformity of a hybrid pressure-controlled loop heat pipe with a heat pipe liner Bomi Nam, Cheongyong Park, Wukchul Joung International Communications in Heat and Mass Transfer.2024; 156: 107656. CrossRef
Progresses in Pneumatic Temperature Control Technique for Ultra-Precise Control and Measurement of Thermal Environment Bomi Nam, Wukchul Joung Journal of the Korean Society for Precision Engineering.2024; 41(10): 759. CrossRef
As the digitization of the manufacturing process is accelerating, various data-driven approaches using machine learning are being developed in chemical mechanical polishing (CMP). For a more accurate prediction in contact-based CMP, it is necessary to consider the real-time changing pad surface roughness during polishing. Changes in pad surface roughness result in non-uniformity of the real contact pressure and friction applied to the wafer, which are the main causes of material removal rate variation. In this paper, we predicted the material removal rate based on pressure and surface roughness using a deep neural network (DNN). Reduced peak height (Rpk) and real contact area (RCA) were chosen as the key parameters indicative of the surface roughness of the pad, and 220 data were collected along with the process pressure. The collected data were normalized and separated in a 3 : 1 : 1 ratio to improve the predictive performance of the DNN model. The hyperparameters of the DNN model were optimized through random search techniques and 5 cross-validations. The optimized DNN model predicted the material removal rate with high accuracy in ex-situ CMP. This study is expected to be utilized in data-driven machine learning decision making for cyber-physical CMP systems in the future.
Citations
Citations to this article as recorded by
Precision Engineering and Intelligent Technologies for Predictable CMP Somin Shin, Hyun Jun Ryu, Sanha Kim, Haedo Jeong, Hyunseop Lee International Journal of Precision Engineering and Manufacturing.2025; 26(9): 2121. CrossRef
Prediction of Normalized Material Removal Rate Profile Based on Deep Neural Network in Five-Zone Carrier Head CMP System Yonsang Cho, Myeongjun Kim, Munyoung Hong, Joocheol Han, Hong Jin Kim, Hyunki Kim, Hyunseop Lee International Journal of Precision Engineering and Manufacturing-Green Technology.2025; 12(3): 869. CrossRef
In this paper, a deburring tool with 3-axis compliance is presented for deburring using a robot manipulator. Compliance is provided with beam structures instead of pneumatic pressure, which enables integrated 3-axis force sensing and variable stiffness. Two radial compliances were achieved using 4-PSS (Prismatic-Spherical-Spherical) legs, with P joints composed of cantilever beams. The one axial compliance was configured with two ball bushings and a linear spring. Strain gauges were attached to cantilever beams and a load cell was mounted between the linear spring and the universal joint to perform force sensing. The stability of vibrations and force sensing were verified through deburring experiments using the proposed deburring tool. Additionally, experiments on automatic offset for applying a constant force during deburring were conducted and results were validated by comparing the workpiece before and after the deburring process.
Citations
Citations to this article as recorded by
Stress Analysis of a Robot End-Effector Knife for the Deburring Process Jeong-Jin Park, Jeong-Hyun Sohn, Kyung-Chang Lee Journal of the Korean Society of Manufacturing Process Engineers.2025; 24(6): 42. CrossRef
Stress Analysis of a Robot End-Effector Knife for the Deburring Process Jeong-Jin Park, Jeong-Hyun Sohn, Kyung-Chang Lee Journal of the Korean Society of Manufacturing Process Engineers.2025; 24(6): 42. CrossRef
Manned water-powered aerial vehicles have been implemented into specialized missions around water bodies, such as firefighting and rescue. However, the dual requirement of vehicle motion control and performing tasks challenges operators. Moreover, in the presence of a low visibility, dense smoke, and extreme temperature, they always face potential risks. Motivated by these difficulties, this paper proposed an unmanned water-powered aerial vehicle using a nozzle rotation mechanism. This mechanism allows the vehicle to have a wide range of forces and torques in multiple directions under constant mass flowrate condition. A simple controller was designed to investigate the fundamental flight motions and verify dynamic properties of the vehicle in practical testing. To come up with the control law, the following steps were taken. Firstly, a mathematical model was derived to reflect the vehicle’s dynamic characteristics. Secondly, a well-known proportional-derivative-integral controller incorporating gravity compensation was deployed to regulate the 3-degree-of-freedom motion system. Thirdly, experiments were conducted to confirm the flight ability of the proposed vehicle. Results demonstrated that the control system preserved stability and the vehicle could fly following the desired altitude.
Citations
Citations to this article as recorded by
Intelligent Robust Motion Control of Aerial Robot Cao-Tri Dinh, Thien-Dinh Nguyen, Young-Bok Kim, Thinh Huynh, Jung-Suk Park Actuators.2025; 14(4): 197. CrossRef
A Hybrid Flying Robot Utilizing Water Thrust and Aerial Propellers: Modeling and Motion Control System Design Thien-Dinh Nguyen, Cao-Tri Dinh, Tan-Ngoc Nguyen, Jung-Suk Park, Thinh Huynh, Young-Bok Kim Actuators.2025; 14(7): 350. CrossRef
In order to monitor the machining status of a machine tool, it is necessary to measure the signal of the machine tool and establish the relationship between the machining status and the signal. One effective approach is to utilize an AIbased analysis model. To improve the accuracy and reliability of AI models, it is crucial to identify the features of the model through signal analysis. However, when dealing with time series data, it has been challenging to identify these features. Therefore, instead of directly applying time series data, a method was used to extract the best features by processing the data using techniques such as RMS and FFT. Recently, there have been numerous reported cases of designing AI models with high accuracy and reliability by directly applying time series data to find the best features, particularly in the case of AI models combining CNN and LSTM. In this paper, time series data obtained through a gap sensor are directly applied to an AI model that combines CNN, LSTM, and MLP (Multi-Layer Perceptron) to determine tool wear. The machine tool and tool status were monitored and evaluated through an AI model trained using time series data from the machining process.
Citations
Citations to this article as recorded by
Development of AI-based Bearing Machining Process Defect Monitoring System Dae-Youn Kim, Dongwoo Go, Seunghoon Lee Journal of Society of Korea Industrial and Systems Engineering.2025; 48(3): 112. CrossRef
A Review of Intelligent Machining Process in CNC Machine Tool Systems Joo Sung Yoon, Il-ha Park, Dong Yoon Lee International Journal of Precision Engineering and Manufacturing.2025; 26(9): 2243. CrossRef
In recent years, research on machine learning techniques that can be integrated with existing suspension control algorithms for enhanced control effects has advanced considerably. Machine learning, especially involving neural networks, often requires many samples, which makes maintaining robust performance in diverse, changing environments challenging. The present study applied reinforcement learning, which can generalize complex situations not previously encountered, to overcome this obstacle and is crucial for suspension control under varying road conditions. The effectiveness of the proposed control method was evaluated on different road conditions using the quarter-vehicle model. The impact of training data was assessed by comparing models trained under two distinct road conditions. In addition, a validation exercise on the performance of the control method that utilizes reinforcement learning demonstrated its potential for enhancing the adaptability and efficiency of suspension systems under various road conditions.
Citations
Citations to this article as recorded by
Control Characteristics of Active Suspension in Vehicles using Adaptive Control Algorithm Jeong Seo Jang, Jung Woo Sohn Transactions of the Korean Society for Noise and Vibration Engineering.2024; 34(5): 568. CrossRef
Suspension Mechanism Design of a Low-platform Target Robot for Evaluating Autonomous Vehicle Active Safety Jae Sang Yoo, Do Hyeon Kim, Jayil Jeong Journal of the Korean Society for Precision Engineering.2024; 41(5): 375. CrossRef
The Glass Molding Process (GMP) produces large quantities of glass optical parts and provides the advantages of high molding accuracy, short production cycle, low cost, and little pollution. Developments in different sectors, such as cameras and telescopes, are prompting studies on the design of aspherical optical components. Modeling heat transfer and deformation at high temperatures are crucial aspects of studying glass because its properties are significantly influenced by temperature-induced phase changes. In this study, temperature changes and geometric deviations of lenses were studied with respect to heating, pressing, and cooling times and the heat capacity of the heater used. A 3D model was designed for the heating, pressing, and cooling steps, and heat transfer was subjected to numerical analysis considering the specific heat of glass and the temperature dependence of thermal conductivity. Lens molding temperature conditions were then analyzed with the heat capacity of the lens molding heating system. Lens molding conditions were derived by analyzing lens temperatures with respect to heating and cooling capacities at each process step.
Citations
Citations to this article as recorded by
Precision glass aspherical lens manufacturing by compression molding: a review Xiaohua Liu, Jian Zhou, Bo Tao, Yang Shu, Zexin Feng, Shih-Chi Chen, Yingying Zhang, Allen Y. Yi Light: Advanced Manufacturing.2026; 7: 1. CrossRef
A Study on Temperature and Stress Distribution in a Lens under Multi-Stage Cooling Conditions in Progressive Glass Molding Processes Ji Hyun Hong, Jeong Taek Hong, Dong Yean Jung, Young Bok Kim, Keun Park, Chang Yong Park Journal of the Korean Society for Precision Engineering.2025; 42(2): 157. CrossRef
Recently, the demand for micromachining of hard materials has been increasing. Machining microholes, grooves, and structures in hard materials such as tungsten carbide is very difficult. In this study, the machining characteristics of a microdisk tool for microgroove machining of tungsten carbide were studied. Microtools made of polycrystalline diamond (PCD) were fabricated using wire electrical discharge grinding (WEDG) to machine high-hardness tungsten carbide. Rectangular and V-shaped disk tools were fabricated by WEDG with controlled wire paths. In the micro grooving of tungsten carbide, the effects of capacitance and feedrate on the surface roughness of microgrooves and the wear of disk tools were studied. As the capacitance and feed rate decreased, the surface roughness decreased and no significant wear was observed in the PCD tool. However, an increase in tool edge radius of several micrometers was observed.
Citations
Citations to this article as recorded by
Micro Hole Machining Characteristics of Glassy Carbon Using Electrical Discharge Machining (EDM) Jae Yeon Kim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2025; 42(4): 325. CrossRef
Prediction of Machining Conditions from EDMed Surface Using CNN Ji Hyo Lee, Jae Yeon Kim, Dae Bo Sim, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(11): 865. CrossRef
Silicon carbide (SiC) is chemically stable, highly heat-resistant, and resistant to thermal shock. SiC having excellent characteristics in a high temperature and high voltage environment is used in high-power semiconductors, highprecision mechanical devices, optical components, etc. As it is used in various industries, there is a growing demand for processing fine holes or grooves in silicon carbide. In this study, micro holes and grooves were machined on 4HSiC and sintered SiC using electrical discharge machining (EDM). Silicon carbide which has very high hardness can be easily processed by EDM as compared with mechanical processes. As a tool material, a polycrystalline diamond (PCD) which has high wear resistance was used and a micro tool of a diameter of 100 μm was fabricated by wire electrical discharge grinding (WEDG). In the EDM of SiC, the machining characteristics such as surface roughness, discharge gap, and tool wear were investigated.
Citations
Citations to this article as recorded by
Micro Hole Machining Characteristics of Glassy Carbon Using Electrical Discharge Machining (EDM) Jae Yeon Kim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2025; 42(4): 325. CrossRef
Prediction of Machining Conditions from EDMed Surface Using CNN Ji Hyo Lee, Jae Yeon Kim, Dae Bo Sim, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(11): 865. CrossRef
With the recent development of 3D printing technology, various 3D printing materials have been developed and used. To utilize 3D-printed products with mechanical parts, studies on friction and wear characteristics according to relative motion between materials are required. However, tribology studies on 3D-printed materials are limited compared to those of the existing materials for mechanical parts. In this study, the frictional and wear characteristics are identified through a reciprocating wear test in non lubricated conditions between the Polylactic Acid (PLA) and Polyethylene Terephthalate Glycol (PETG) printed in the Fused Deposition Modeling (FDM) method. In the wear test between the same materials, the friction coefficient and wear rate were higher in the PLA than in the PETG, and PLA was deposited on the block due to high frictional heat. In the wear test of the PLA block and PETG bump, the wear of the PLA block decreased compared to the wear test between the same materials, but the wear of the PETG bump tended to increase. Therefore, it seems that the 3D-printed PETG may be more advantageous in terms of friction and wear than 3D-printed PLA during relative movement in a non lubricating condition.
Citations
Citations to this article as recorded by
Tribological Properties of Fused Deposition Modeling-Printed Polylactic Acid and PLA-CF: Extrusion Temperature and Internal Structure Paweł Zawadzki, Justyna Rybarczyk, Adam Patalas, Natalia Wierzbicka, Remigiusz Łabudzki, Băilă Diana, Fodchuk Igor, Bonilla Mirian Journal of Tribology.2026;[Epub] CrossRef
Artificial Intelligence Technologies and Applications in Additive Manufacturing Selim Ahamed Shah, In Hwan Lee, Hochan Kim International Journal of Precision Engineering and Manufacturing.2025; 26(9): 2463. CrossRef
Here in, a high-quality automotive camera lens was developed based on an ultra-precision diamond turning core and cyclic olefin polymer (COP) injection molding process. To improve surface roughness and achieve the accuracy of plastic injection molding lens, systematic mold core machining process was developed and demonstrated using the diamond turning machine. The cutting tool path was generated by using NanoCAM 2D, and it was partly revised to prevent interference between the cutting tool and the workpiece. After the initial machining using the generated tool path, the compensation-cutting process was conducted based on the measured surface profile of an initially machined surface. After two times of compensation machining, the fabricated core mold showed a shape error of 100 nm between peak to valley (PV) and Arithmetic mean roughness (Ra) of 3.9 nm. The performance of the fabricated core was evaluated using an injection molding test. Injection molded aspheric plastic lens showed contrasts that were higher than 55% at 0.0 F, 30% at 0.3 F, and 20% at 0.7 F without any moiré phenomenon that meets the specification for automotive vision module with 1MP and 140° field of view.
Citations
Citations to this article as recorded by
Research progress on grinding contact theory of axisymmetric aspheric optical elements Wenzhang Yang, Bing Chen, Bing Guo, Qingliang Zhao, Juchuan Dai, Guangye Qing Precision Engineering.2026; 97: 24. CrossRef
Performance enhancement of material removal using a surface-refinement model based on spatial frequency–response characteristics in magnetorheological finishing Minwoo Jeon, Seok-Kyeong Jeong, Woo-Jong Yeo, Hwan-Jin Choi, Mincheol Kim, Min-Gab Bog, Wonkyun Lee The International Journal of Advanced Manufacturing Technology.2024; 135(11-12): 5391. CrossRef
In this study, we present a numerical simulation approach for designing Fresnel zone plate (FZP) patterns. By optimizing surface phase parameters using desired merit functions in ray-tracing software, the obtained surface phase was converted into an FZP pattern through a 5-step procedure. A comparison between our numerical simulation approach and the traditional analytical method showed a negligible zone size difference of 0.606 nm and nearly absolute agreement of 17.549 μm in focal spot size. The FZP pattern was experimentally verified by an expected focal spot size of 18.55 μm. Our approach demonstrated design flexibility and has potential applications in simulating various functionalities in FZP patterns and refractive-diffractive hybrid lenses to address specific optical challenges. The surface phase can be freely modified based on optimization objectives that cannot be achieved using the analytical approach, ensuring high-precision design for accurate extraction.
Citations
Citations to this article as recorded by
Mechanistic evaluations of radial fiber tip for circumferential laser ablation Minh Duc Ta, Jiho Lee, Seonho Jung, Van Gia Truong, Hyun Wook Kang Optics & Laser Technology.2025; 192: 113660. CrossRef
Quantitative investigations on light emission profiles for interstitial laser treatment Minh Duc Ta, Yeongeun Kim, Hwarang Shin, Van Gia Truong, Hyun Wook Kang Biomedical Optics Express.2024; 15(12): 6877. CrossRef
The fourth industrial revolution led to advanced servo systems, enhancing productivity across industries. However, designing these systems remains challenging due to the performance-stability trade-off. This paper presents a model-based motion control of a linear motor motion stage in frequency domain. A user-code for the PowerPMAC commercial controller was developed to excite motion control system so that we could get a frequency response. The theoretical frequency response of the servo algorithm was compared with the experimental frequency response. Based on this, a tuning graphical user interface (GUI) was developed to predict performance when the servo loop gain is changed. Especially, to compensate for residual vibrations caused by high acceleration and deceleration and to improve tracking error, DOB (Disturbance Observer) and ILC (Iterative Learning Control) control techniques were applied in the frequency domain. Through the design of the frequency domain motion controller, the control performance of the linear motor motion stage could be predicted with over 96% accuracy, resulting in a 54.32% improvement in tracking error and a 93.56% improvement in settling time, 85.29% in RMS error.
Citations
Citations to this article as recorded by
Fuzzy Neural Network Control for a Reaction Force Compensation Linear Motor Motion Stage Kyung Ho Yang, Hyeong-Joon Ahn International Journal of Precision Engineering and Manufacturing-Smart Technology.2024; 2(2): 109. CrossRef
Customized Current Control of a Linear Motor Motion Stage Kyung Ho Yang, Hyeong-Joon Ahn Journal of the Korean Society for Precision Engineering.2024; 41(11): 875. CrossRef
First
Prev
